For protection of inflammable and non-inflammable building materials, and constructional parts, coating materials are used, which can be coated onto the object to be protected, in the manner of a coating-compound. In the event of fire, i.e. under the action of heat, such coatings develop a heat-insulating foam layer which hinders the action of the heat upon the coated object. In this way, wood can be made "not easily inflammable," and the "fire-resistance duration" of steel constructional parts can be considerably prolonged. Generally, the coating materials consist of urea-and/or dicyanodiamide-formaldehyde condensates, with a content of phosphates, e.g. monoammonium orthophosphate and further additives such as carbohydrates and optionally fillers such as silicic acid or kaolin. In many cases they are aqueous preparations, and therefore they have the disadvantage that it is difficult to wet smooth undersurfaces such as steel which have been coated with primer, or synthetic plastics material surfaces. Coatings made from these are caused to swell up by the moisture in the air, and are comparatively rapidly dissolved by condensed water; which, of course, quickly leads to a loss of the fire-retardant action.
Similarly-prepared fire-retardant compositions also are known, which do not contain water, but organic solvents. It is true that these are easy to use and can result in coatings which are more water-resistant; however they have the disadvantage that they are inflammable when in the supplied condition. During the application and/or the drying of the coating, the organic solvents have to be vapourised; therefore, corresponding protective measures are necessary.